1. Field of the invention
This invention is in the field of noise suppression and sound absorption for noisy machines and devices.
2. Description of the prior art
In many places noisy machines are objectionable and a public nuisance. In the prior art, such noise was suppressed by use of noisy sound absorbing materials placed around the machine. These prior art sound absorbing materials are commonly solids, often in fibrous or particle form, such as fiberglass mats, wood fiber mats, sawdust inclosed between boards, acoustic tiles, etc. Almost any degree of noise suppression can be achieved by use of a sufficient thickness of these prior art sound absorbers but the cost is thusly increased and more space is taken up as greater noise suppression is achieved. It would be desirable to have available a sound absorbing material of great effectiveness at small thicknesses.
A typical and common example of a noisy machine is the internal combustion engine such as the gasoline engine, as used in automobiles, and the diesel engine, as used in automobiles, trucks, and buses. Most of theses internal combustion engines are liquid cooled and are thus fitted with a cooling jacket which surrounds the engine cylinder and combustion chamber. This cooling jacket is also a means for containing a fluid and is fitted with a fluid inlet and a fluid outlet. Wood chippers for chopping up tree wastes are another example of a noisy machine. High speed blowers such as are used in some industrial type vacuum cleaners and blowers are also usually very noisy as are some types of high pressure hydraulic pumping devices.